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Oct. 15, 1929. R. MALVOS ET AL FURNACE Filed Nov. 14, 1924 6 Sheets-Sheet l Oct. 15, 1929. R. MALVOS ETAL 1,731,901

FURNACE Filed Nov. 14, 1924 s Sheets-Sheet 2 Get. 15, 1929.

R. MALVOS ET AL FURNACE Filed Nov. 14, 1924 6 Sheets-Sheet 5 Oct. 15, 1929. R. MALVOS ET AL FURNACE Filed NOV. 14, 1924 6 Sheets-Sheet 4 Oct. 15, 1929. R. MALVOS ET AL 1,731,901

FURNACE Filed Nov.- 14, 1924 6 Sheets-Sheet 5 mm Mm Oct. 15, 1929. R. MALVOS ETAL 1,731,901

FURNACE Filed Nov. 14, 1924 6 Sheets-Shegt 6 l i MW 7 y Patented Oct. 15, 1929 UNITED STATES PATENT OFFICE ROBERT MALVOS, F CHARTRES, AND MARCELLIN CROZEMARIE, OF DREUX, FRANCE romance Application filed November 14, 1924, Serial No. 750,003, and in Trance November 11, 1923.

This invention relates to a furnace in which a temperature of 1800 C. can be reached, so that the said furnace can be used for burning refractory products, abrasives, grinding fi stones and all other substances or materials requiring such a temperature.

The invention is chiefly intended for me dium sized works where it is not practicable to use continuous furnaces, and it renders possible the use of fuel which is easy to get and is not liable to enormous fluctuations in price such as heavy oils.

The division of this furnace into at least three units arranged side by side, makes it possible to Work in a continuous manner with intermittent units. This combination, together with the special arrangement of the furnaces and with the use of recuperation chambers, makes it possible to ensure a high thermal efliciency of the fuel.

This furnace has moreover various other new features in its construction:

A double system of air supply, either by suction due to the draught, with preliminary heating of the air around the furnace, or by injecting air by means of a fan or blower after passage through a recuperator.

A series of collecting recesses for the gases, provided in the longitudinal walls of the burning chambers.

Progressive cooling of the units after the burning period by pumping out the hot gases from the top of a unit by means of a fan and by admitting a proportional quantity of fresh air at the bottom. I

Introduction or charging and Withdrawal or discharge of the products or material through the roof of the furnace, and construction of the arch by removable or detachable panelsfor thepurpose of making such operations possible.

Constructional details of this furnace are shown by way of example in the accompanying drawings, in which:

Figure 1 is a longitudinal section on line 11 of Figure 3, of one burning chamber.

Figure 2 is a side elevation and cross-section of one unit, taken on line 2-2 of Figure 3.

Figure 3 is a horizontal section.

F igure l is an enlarged detail cross section along the line H of Figure 3.

Figures 5 and 5 are plain views conjointly showing the general arrangement of a furnace with three units and of its recuperator.

Figure 6 is a plan of the top of an arch.

Figures 7 and 8 are two cross-sections on lines 77 and 8-8 of Figure 6. 1

v igures 9 and 10 are two longitudinal sections on lines 99 and 101O of Figure'6.

The furnace comprises several (for instance three) burning chambers 1, one of which is working while the second one is being cooled, and the third is ready to be fired. The brickwork 2 is surrounded by metal hoops or bands 3 provided with springs 4 (Figures 2 and 5) which always ensure proper clamping in spite of different coeflicient of expansion, and reduce the stresses both on the metal and on the brickwork. Gas collecting recesses 5 are provided along the lateral wallsof the furnace, and windows 6 allow the burning to be watched.

Theheating of each compartment is effected by four (or more) furnaces 7. Each furnace, which has the shape of a U, is provided with cross bars 8 of refractory material and comprises two grates 9 and 10. It is charged by means of a hopper 11.

Two windows are provided at 12 and 13 a for the purpose of watching the furnace, and when they are opened, one of them makes it possible to slice or rake the descending column of fuel and the upper grate 9, and the other the slicing or raking of the lower grate 10.

The first window 12 provided in the vertical wall of the furnace, is closed by means of a pottery plug, and the other window 13 is formed through a tank 16, and its outside face is provided with a movable shutter fitted with mica. This latter window makes it possible always to watch the state of the fire. Inspection of the furnace and lighting thereof are effected through the door 14.

A concrete water trough 15 forms an ash pit under the grate 10.

The tank 16 is arranged in front of the upper grate. It is erforated at the top on the face facing the re. These two tanks 15 and 16 protect the grates and facilitate the combustion in the furnace.

A tank 16, which is provided with a float cock, as shown in Figure 1, feeds all the ash pits on one side.

The discharge of the products of combustion and the draught take place through openings 17 provided in the sole or hearth, the fines 18, the main flue 19 and the collector flue 20 leading to the chimney 21 (Figures 5 and 5 either directly or after passage through the recuperator 22 (Figure 5). The draught is regulated by means of a damper of refractory material 23 (Figures 2 and 4) arranged in the main flue of each unit, adjacent which damper terminates a suction conduit 24 in tended to admit a more or less large quantity of fresh air into a compartment.

The supply of air to the furnace in normal working is effected through conduits 2 provided in the masonry around the furnaces in order that the air admitted through orifices 26 (Figure 2) more or less closed by sliding doors with balance weights 27, shall be sub jected to a preliminary heating. As soon as the temperature reaches 500 0., forced ventilation is produced by a fan 28 driven by an electric motor 29 (Figure or by any other motor, for instance with utilization of the waste gases.

, The air. drawn from the recuperator through the pipe 30 by the action of Ian 28 is forced into the main pipe 31, whence is distributed to the furnaces by means of valves 32 and piping 33. This piping, the output of which is regulated by means of cocks 34, terminates under the furnace, thus aisisting the combustion, (see Figures 1 and 2 The progressive cooling of the furnaces after burning can be carried out owing to the nozzle 35 (Figure 5) projecting into the conduit 43, the output of which can be regulated in accordance with requirements by means of a sliding damper 35''. With this device it is easy to draw in the desired quantity of hot gases into a furnace to be cooled. The corresponding admission of fresh air takes place through the sliding damper 23 (Figures 2 and 4).

Apart from the recuperation already obtained by the method just described, another independent recuperation takes place in the following manner; the products of combustion coming through the collector flue 20 are directed, by means of two slide valves 36 and 37 (Figure 5 either directly into the chimney 21 through the conduit 38, or into flues 39, said flues making a circuit of the recuperator 22. Air drawn from the outside at the base of the chimney is admitted through pipes 40 into the conduits 41 (Figure 5) extending along the walls of the smoke and hot gas flues. The air thus heated escapes through suitable orifices into the recuperation chamber 22, which latter is divided into several communieating compartments from which it is drawn by the pipe 30 of the fan.

The introduction or charging of the products to be burnt is effected by means of an overhead traveller, trucks or small cranes through charging doors 44, four per unit (Figures 610); this number, sufficient in most cases, can vary according to requirements. A narrow width of fixed arch 45 is left at the key and forms a cross along the two axes of each burning chamber. The two longitudinal branches of the arch are constituted by plates 46 engaging on the one hand with the arch key 45 and on the other hand with the piers of the furnace (Figure 7), they are connected together by tenons and mortises, and the two lower parts carry a rebate 47 (Figures 8 and 10). The closing parts 48 for the door rest at one side in a recess provided in the pier, and at the other side in the rebate 47 of the parts 46. They are provided with iron hooks 49, sealed in shoulders provided for the purpose, for rais ing them or putting them in place. Finally a refractory grouting or filling 5O completes the closing.

According to the use to which the furnace may be put, the arch 45 may be done away with completely and replaced by supporting panels 46 and traps or leaves or flaps 48, the grouting 50 still ensuring air tight closing during the burning.

The working of a furnace of the above construction is as follows:

The material or products to be charged, are brought by means of an overhead traveller or of any other desired hoisting and transporting apparatus, to a point above one of the upper openings 44 and lowered into the furnace to the place which they kee) during the burning, without being touche d by the hand of a workman. This greatfacility of putting in place and complete absence of any handling eliminates all risk of damage, shocks or chipping of the parts which are always fragile.

The furnace having been charged, the traps 48 suspended by means of their hooks 49 from the overhead traveller, are lowered and put in place, and the empty spaces are filled to the upper level by refractory grouting 50.

The furnace unit being closed, shavings and bits of wood are introduced into the hopper 11, the door 14 is opened, and the fire is lighted. The draught dampers 23 (Figure 4) and the direct discharge dampers 37 (Figure 5*") must be open; the, breather of the suction conduit 24 (Figure 4) must be closed, and the damper 36 for circulation in the recuperator 22 (Figure 5*) closed. The door 14 is then closed; this door must never be opened during the burning and must not be used except at the moment of lighting or for inspection and repairs when the furnace unit is not working. Wood is supplied for several hours, then coal, the temperature being raised only slowly so as to enable the water vapours to escape from the products to be burnt without in any way injuring them. This method of work,- ing is however essential only when the products to be burnt have not been previously treated in drying kilns. During this first stage, the admission of air takes place with heating through the conduits 25 and is regulated by the manipulation of the doors 27 closing the openings 26. But as soon as the temperature reaches 500 (1, the damper 36 is opened, and the damper 37 closed, in order to cause the gases to circulate in the recuperator 22 (Figure 5 the ventilating fan 28 is started, the valves 32 of the conduits 33 of the working unit of the furnace are opened, and the doors 27 closed.

The fire is watched and supervised through the Windows 12 and 13, and the raking or slicing of the grates 9 and 10 is also done through the said windows. The supervision of the fusing is done through the win dows 6. The temperature at each burning operation must be raised to 1800 (l, and such operation must last from 80 to 90 hours.

When the burning is finished, the prodnets are cooled by opening the dampers 35 and 23 in order to draw the hot gases through the pipe 43 and allow fresh air to enter through the conduits '24; and 19.

After cooling, the grouting 50 is removed, the traps 48 are raised by means of the hoisting apparatus, and the products are suspended, withdrawn from the furnace and charged on trucks arranged on a track parallel to the furnace, by means of the overhead traveller, or transported by it into a Warehouse. The utilization of openings in the roof of the furnace, instead of lateral doors, makes it possible to effect a considerable saving of time and labour.

During that time, another unit has been fired so that the working of the battery is continuous with intermittent units provided with a common recuperator, which ensures continuous utilization of shifts of expert cial construction of the arch by means of ,detachable panels facilitating the charging,

are applicable to all kinds of furnaces.

What we claim as our invention and desire to secure by letters patent is 1. A furnace, comprising a working chamher; a lateral hearth in the form of a vertical U associated with said chamber to heat the same and provided with a pair of spaced grates; and a protective water tank opposite cach grate.

2. In a furnace, a working chamber; a lateral hearth in the form of a vertical U associated with said chamber to heat the same and provided with a pair of spaced grates; and a protective water tank opposite each grate, one of such tanks embodying a water jacket having a window formed transversely through it to permit inspection of and access to the corresponding grate.

3. In a furnace, a working chamber; a lateral hearth in the form of a vertical U associated with said chamber to heat the same and provided with upper and lower grates; a protective water tank opposite each grate, the tank associated with the lower grate forming an ash pit; and a system of fines formed in the walls of the chamber for' preheating air and discharging it beneath the grates.

t. In a furnace, a working chamber; a lateral hearth in the form of a vertical U' associated with said chamber to heat the same and provided with upper and lower grates; a protective water tank opposite each grate, the upper tank embodying a water jacket having a window formed transversely through it to permit inspection of and access to the upper grate, and the lower tank constituting an ash pit; and means for delivering heated air beneath the grates.

In testimony whereof we have signed our names to this specification.

ROBERT MALVOS. MAROELLIN CROZEMARIE.

workmen, and a high calorific efiiciency by the recuperation.

The dimensions of the furnace, the number of units constituting the battery, and the number of furnaces per chamber and of charging traps, vary according to the applications, and the arrangements of metal hoops or hands, of air supply conduits and of gas discharge conduits can be easily modified to suit the requirements of each individual case.

The method of binding by non-rigid hoops owing to the addition of helical springs allowing for expansion, and thespe- 

